81768847 has 2 divisors, whose sum is σ = 81768848. Its totient is φ = 81768846.

The previous prime is 81768829. The next prime is 81768923. The reversal of 81768847 is 74886718.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81768847 is a prime.

It is a super-2 number, since 2×81768847² = 13372288679418818, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81768847.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81766847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40884423 + 40884424.

It is an arithmetic number, because the mean of its divisors is an integer number (40884424).

Almost surely, 2^81768847 is an apocalyptic number.

81768847 is a deficient number, since it is larger than the sum of its proper divisors (1).

81768847 is an equidigital number, since it uses as much as digits as its factorization.

81768847 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 602112, while the sum is 49.

The square root of 81768847 is about 9042.6128414303. The cubic root of 81768847 is about 434.0395367720.

The spelling of 81768847 in words is "eighty-one million, seven hundred sixty-eight thousand, eight hundred forty-seven".